Catheter system having a balloon angioplasty device disposed over a work element lumen

ABSTRACT

An intravascular catheter system has a balloon angioplasty device disposed about a common lumen near its distal end. The common lumen is in communication with multiple lumens within a proximal region of the catheter body to allow for positioning of the catheter over a movable guide wire and convenient delivery of imaging or interventional devices to a desired region of the blood vessel being treated.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a continuation of co-pending U.S.patent application Ser. No. 09/379,930, filed on Aug. 23, 1999, which isa continuation of U.S. patent application Ser. No. 08/861,397, filed onMay 21, 1997, now U.S. Pat. No. 5,941,870, which is a continuation ofU.S. application Ser. No. 08/504,363, filed on Jul. 19, 1995, nowabandoned, which is a continuation of U.S. application Ser. No.08/291,215, filed on August 16, 1994, now abandoned, which is acontinuation of U.S. application Ser. No. 08/100,642, filed on Jul. 30,1993, now U.S. Pat. No. 5,364,347, which is a continuation of U.S.application Ser. No. 07/975,752, filed on Nov. 13, 1992, now abandoned.The priority of these prior applications is expressly claimed and theirdisclosures are hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates generally to catheter systems forimaging and treatment of stenoses within a patient's vascular system andmore particularly to a catheter system in which a balloon angioplastydevice can be delivered along with an imaging or interventional workelement to a desired region within a blood vessel.

[0004] 2. Description of the Background Art

[0005] Arteriosclerosis, also known as atherosclerosis, is a commonhuman ailment arising from the deposition of fatty-like substances,referred to as atheroma or plaque, on the walls of blood vessels. Suchdeposits occur both in peripheral blood vessels that feed limbs of thebody and coronary blood vessels that feed the heart. Localizedaccumulation of deposits within regions of the blood vessels may resultin stenosis, or narrowing of the vascular channel. When this occurs,blood flow is restricted and the person's health is at serious risk.

[0006] Numerous approaches for reducing and removing such vasculardeposits have been proposed, including balloon angioplasty, in which aballoon-tipped catheter is used to dilate a stenosed region within theblood vessel; atherectomy, in which a blade or other cutting element isused to sever and remove the stenotic material; laser angioplasty, inwhich laser energy is used to ablate at least a portion of the stenoticmaterial; and the like.

[0007] In order to apply such intervention techniques more effectively,a variety of vascular imaging devices and methods may be employed. Ofparticular interest to the present invention, imaging catheters havingultrasonic transducers at their distal ends have been employed toproduce images of the stenotic region from within the blood vessel. Anumber of specific designs for ultrasonic imaging catheters have beendescribed. An early design is illustrated in U.S. Pat. No. 4,794,931,where the mechanical components of the imaging system are located withina housing at the distal end of the catheter. The housing includes afixed guidewire, which is used to position the catheter within thevascular system, at its distal tip. While the use of such fixedguidewire designs can provide excellent image quality, under somecircumstances it is desirable to use an “over the wire” design where thecatheter may be introduced over a separate (movable) guidewire. The useof A movable guidewire offers certain advantages, including improvedsteering capability through narrow regions and easier catheter exchange,e.g., substitution of an interventional catheter for the imagingcatheter.

[0008] Exchanging the imaging catheter for an interventional or othercatheter within a patient's vascular system is time consuming and may beinjurious to the patient. It is desirable therefore to combine imagingand interventional capabilities in a single catheter system. A designfor an ultrasonic imaging catheter having a balloon angioplasty deviceis described in U.S. Pat. No. 5,117,831. One depicted embodiment uses afixed guidewire and is thus subject to the disadvantages noted above.Another embodiment has a guidewire movable through the ultrasonicimaging transducer and its associated drive shaft. This requires thatthe transducer and the drive shaft be made hollow and increased indiameter in order to accommodate the guidewire therein. Additionally,the transducer is fixed at the end of the drive shaft and not movablealong the length of the catheter.

[0009] To be able to cross very narrow lesions, the diameter of thecatheter should be as small as possible at its distal end. Furthermore,the need to move the catheter body within the patient should beminimized. The blood vessel interior is delicate, may be weakened bydisease, and is therefore susceptible to injury from movement of thecatheter body within it.

[0010] For the reasons stated above, it would be advantageous to providea catheter capable of delivering a balloon angioplasty system incombination with an imaging or interventional work element to a regionof interest within the vascular system. Such delivery should beaccomplished with a minimum repositioning of the catheter body withinthe blood vessel. Additionally, the catheter should be as narrow aspossible at its distal end to allow for entry into and through narrowand tortuous regions of the patient's vascular system.

SUMMARY OF THE INVENTION

[0011] The present invention provides a catheter system having theability to deliver both an angioplasty balloon and another work elementfor imaging or treating a region within patient's vascular system. Thecatheter system comprises a catheter body having at least a proximal anda distal region. The proximal region has at least two lumens, one forcarrying a movable guidewire and another for carrying a work element.The work element will typically be an ultrasonic imaging transducer butmay be another imaging device or even an interventional device fortreating the blood vessel in combination with the angioplasty balloon.The distal region of the catheter body has a common lumen connected toand in communication with the two lumens of the proximal region. Theangioplasty balloon is disposed about the common lumen of the distalregion, and the catheter system further includes an associated means forinflating the balloon, typically an inflation lumen extending from theproximal end of the catheter body to the balloon.

[0012] The catheter of the present invention will allow for theperformance of rapid and convenient balloon angioplasty and imaging orother treatment of the diseased vessel while minimizing the need toreposition the catheter body between procedures. Additionally, thedistal end of the catheter fill be relatively narrow to allow formovement of the catheter into restricted spaces of the patient'svascular system and particularly into narrow regions and stenoses withinthe coronary arteries.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 depicts a preferred embodiment of a catheter according tothe present invention;

[0014]FIG. 2A is a cross-sectional view through section line A-A of thecatheter depicted in FIG. 1;

[0015]FIG. 2B is a cross-sectional view through section line B-B of thecatheter depicted in FIG. 1;

[0016]FIG. 3 depicts a transition region between proximal and distalregions of the body of the catheter depicted in FIG. 1; and

[0017]FIG. 4 depicts the transition region and distal region of analternate preferred embodiment of a catheter according to the presentinvention.

DESCRIPTION OF SPECIFIC EMBODIMENTS

[0018] A catheter according to the present invention will comprise anelongate catheter body having proximal and distal ends and at least tworegions, a proximal region and a distal region. The proximal region ofthe catheter body will have at least two lumens extending at leastpartly therethrough. The distal region of the catheter body will have asingle common lumen in communication with both of the lumens of theproximal region. Additionally, an inflatable angioplasty balloon will bedisposed about the common lumen of the distal region of the catheter.

[0019] In use, a catheter according to the present invention will beadvanced over a guidewire into a patient's vascular system. First, theguidewire will be advanced alone into the patient until the guidewirelies within a particular region of interest. This will typically be aregion in which a blood vessel has been narrowed by a stenotic lesion.The distal end of the guidewire will be advanced into the region ofstenosis with the proximal end of the guidewire remaining outside of thepatient's body.

[0020] The proximal end of the guidewire may then be-inserted into thedistal end of the catheter body and fed through the common lumen of thedistal region. When the proximal end of the guidewire reaches atransition region between the distal and proximal regions of thecatheter body, the guidewire will be directed into a particularguidewire lumen of the proximal region.

[0021] Once the guidewire has been directed into the guidewire lumen,the catheter will be advanced into the patient's vascular system untilthe common lumen of the distal region lies within the region ofinterest. During advancement of the catheter into the blood vessel, theproximal end of the guidewire will exit the catheter body through aguidewire port located some distance proximal of the distal region (ineither an “over-the wire,” configuration, or a “monorails”configuration). The proximal end of the guidewire may then be graspedand pulled back sufficiently to withdraw the distal end of the guidewireinto the guidewire lumen and clear of the common lumen of the distalregion. An ultrasonic imaging transducer or other work element may thenbe advanced through another lumen of the proximal region and into thecommon lumen for imaging the region of interest.

[0022] Prior to inflation of the balloon, the imaging element willnormally be withdrawn from the common lumen into its lumen in theproximal region. The guidewire will then be readvanced through thecommon lumen and into the blood vessel.

[0023] At present, it is highly advantageous for the guidewire to be inplace in the common lumen when the balloon is inflated. When the balloonis inflated, blood flow through the blood vessel will be blocked by theballoon. An adverse ischemic condition may result and rapid removal ofthe catheter from the blood vessel may be required. If the guidewire isin position in the common lumen, rapid catheter removal will be madeeasier. Additionally, replacement of the catheter over the guidewirewill be more convenient once the ischemic condition has abated.

[0024] After the initial balloon inflation, successive steps of imagingand dilation may be repeated as desired. Alternatively, some other formof interventional device, for example, a mechanical cutter or laserablation device, may be advanced through the distal tip of the catheterbody.

[0025] Thus, a catheter according to the present invention will allowfor the convenient delivery of a balloon angioplasty device incombination with another interventional or imaging device to a region ofinterest within the patient. Because the catheter uses a single commondistal lumen, it may be made with a reduced profile at its distal end.This will allow delivery of the balloon angioplasty imaging, or otherinterventional devices even within narrow, tortuous regions of thepatient's vascular system. Furthermore, the various work elements aredelivered through a common lumen lying within the balloon, thusminimizing the need to reposition the catheter body between treatmentsteps.

[0026]FIG. 1 depicts a preferred embodiment of a catheter according tothe present invention. The catheter has a catheter body 12, whichcomprises proximal region 15, distal region 18, and transition region20. FIG. 2A is a cross-sectional view of the proximal region of catheterbody 12 through section line A-A. In this embodiment, proximal region 15has three lumens, work element lumen 23, guidewire lumen 25, andproximal balloon inflation lumen 27. Other embodiments could have stillmore lumens to accommodate additional imaging or interventional devices,as described generally in U.S. Pat. No. 5,997,523, the full disclosureof which is incorporated herein by reference. Guidewire port 30 andballoon inflation port 32 (FIG. 1) place guidewire lumen 25 and proximalballoon inflation lumen 27 in communication with the exterior of thecatheter near its proximal end.

[0027] In the embodiment depicted in FIG. 1, drive shaft 45 isreciprocatably disposed within work element lumen 23. (For clarity, onlya distal portion of drive shaft 45 is illustrated). At its proximal end,work element lumen 23 is in communication with expandable member 39,which is connected in turn to proximal housing 35. The proximal housingis adapted to connect a proximal end of drive shaft 45 to a drive motor(not shown) for rotating the drive shaft.

[0028] Expandable member 39 allows the drive shaft to be convenientlyadvanced and retracted within work element lumen 23 by moving proximalhousing 35 with respect to the catheter body to lengthen or shortenexpandable member 39 as desired. Proximal housing 35 is provided furtherwith flush port 50, to allow for the flushing of trapped air bubblesfrom within work element lumen 23. The construction and use of proximalhousing 35 in conjunction with a multi-lumen catheter is more fullydescribed in U.S. Pat. No. 5,314,408, the full disclosure of which isincorporated herein by reference.

[0029] A cross-section through distal region 18 of catheter body 12through section line B-B is depicted in FIG. 2B. As can be seen therein,distal region 18 has two concentric lumens. In the distal region, commonlumen 60 is disposed within distal balloon inflation lumen 62.

[0030] Referring again to FIG. 1, balloon 65 is disposed about commonlumen 60. The balloon is in communication with distal balloon inflationlumen 62 to provide for inflation of the balloon. Radiopaque band 68 iswrapped around the common lumen at a position within the balloon toallow for fluoroscopic imaging to assist in placing the balloon withinthe desired region of the blood vessel.

[0031] The length of common lumen 60 will generally be between 5 and 30centimeters, with balloon 65 typically having a length in the range of1.5-4.5 centimeters. The balloon crossing profile, the minimum widthcrossable by the balloon when deflated, will typically be in the rangeof 0.020-0.045 inches. The outside diameter of the balloon when inflatedwithin a blood vessel will commonly be between 1.5 and 4.5 millimeters.The foregoing ranges are set forth solely for the purpose ofillustrating typical device dimensions. The actual dimensions of adevice constructed according to the principles of the present inventionmay obviously vary outside of the listed ranges without departing fromthose basic principles.

[0032]FIG. 3 depicts transition region 20 between the three parallellumens of proximal region 15 and the two concentric lumens of distalregion 18. Transition region 20 provides for communication betweencommon lumen 60 of the distal region and both guidewire lumen 25 andwork element lumen 23 of the proximal region. Also, distal ballooninflation lumen 62 is placed in communication with proximal ballooninflation lumen 27 through balloon inflation lumen connection 70, whichis formed by cutting through the exterior of proximal region 15 toexpose a portion of the proximal balloon inflation lumen and sealing theend of the balloon inflation lumen to close it off from common lumen 60.Thus, a continuous inflation path exists from balloon inflation port 32Fthrough proximal and distal balloon inflation lumens 27 and 62, and intoballoon 65. Injection of fluid into balloon inflation port 32 willthereby result in inflation of balloon 65.

[0033] It is contemplated that the catheter depicted in FIG. 1 will beused as follows. First, a conventional guidewire will be advanced intothe patient's vascular system until it lies within the region ofstenosis. Next, the guidewire will be inserted into distal tip 77(FIG. 1) of the catheter and through common lumen 60 of distal region18. The catheter will then be advanced into the patient's body over theguidewire until the guidewire reaches transition region 20. At thispoint, the guidewire will be directed into guidewire lumen 25 andthrough the proximal region until it exits the catheter throughguidewire port 30 as the catheter is advanced further into the patient'sbody. Eventually, the catheter will be advanced to a point where commonlumen 60 and balloon 65 both lie within the region of interest.

[0034] The operator of the system can then grasp the guidewire at theend protruding from the guidewire port. The operator will pull theguidewire back a short distance into guidewire lumen 25 of proximalregion 15 in order to clear common lumen 60 of distal region 18. A workelement 75, which will typically be an ultrasonic imaging transducer,fixed to the distal end of drive shaft 45, may then be advanced throughwork element lumen 23 of the proximal region and into the common lumenof the distal region. Imaging of the region of interest may then takeplace.

[0035] Following imaging, work element 75 will be retracted into itslumen in the proximal region. The guidewire will be readvanced throughthe common lumen into the blood vessel. Balloon 65 may then be inflatedto dilate the region of interest and thereby reduce the stenosistherein. Successive steps of imaging, guidewire replacement, andtreatment may be repeated as desired until the stenosis has beensatisfactorily reduced. If complications result due to restriction bythe balloon of blood flow through the vessel, the catheter may bequickly and conveniently pulled back over the guidewire to restore bloodflow through the vessel.

[0036]FIG. 1 depicts a catheter in which the common lumen is narrowed ata restriction 80 just proximal to the balloon. Distal of therestriction, the common lumen will be just large enough to allow passageof the guide wire. This allows the balloon crossing profile, the widthof the catheter in the region of the balloon when not inflated, to be assmall as possible. This is advantageous in that it allows the balloon'tobe advanced into narrow and tortuous regions of the blood vessel.Placing the restriction proximal to the balloon is disadvantageous,however, in that it may prevent entry of the work element into thecommon lumen within the balloon. Thus, some repositioning of thecatheter body within the blood vessel, i.e., advancement of the catheterbody a further into the blood vessel, may be necessary to allow forimaging of the treated region.

[0037]FIG. 4 depicts the distal region of an alternative preferredembodiment in which the common lumen is not restricted in the regionproximal to the balloon. In this embodiment, the work element may travelthrough the common lumen into, through and beyond the balloon. This isadvantageous in that it allows for imaging of the blood vesselthroughout the region of the balloon without repositioning the catheterbody.

[0038] As discussed above, it is desirable at present to have theguidewire in place within the common lumen during balloon inflation incase rapid withdrawal of the catheter over the guidewire becomesnecessary. However, future developments in interventional devices andtechniques may make this unnecessary. If this becomes the case, imagingwill be possible from within the balloon even while the balloon is beinginflated. Of course, an increased diameter common lumen within theballoon requires a slightly larger balloon crossing profile. Someability to enter narrow regions must thereby be sacrificed in order toachieve a more flexible imaging capability.

[0039] The embodiment of FIG. 4 depicts the common lumen havingrestriction 80 at some distance distal to balloon 65. This restrictionwill prevent the accidental exit of the work element from the distal tip77 of the catheter body while still allowing passage of the guidewire.This prevents injury to the blood vessel wall, which might result fromaccidental contact by the rotating work element. A catheter according tothe present invention could also be made to carry an interventional workelement such as a rotating cutter or a laser ablation device. In such acase, it would be necessary for the work element to advance beyond thedistal tip 77 of the catheter body. In such a catheter system,restriction 80 would be omitted altogether to allow for unhinderedpassage of the work element.

[0040] Although the foregoing invention has been described in somedetail by way of illustration and example for purposes of clarity ofunderstanding, it will be obvious that certain changes and modificationsmay be practiced which will still fall within the scope of the appendedclaims.

1-12. (cancelled)
 13. A catheter system comprising: a catheter bodyhaving proximal and distal ends, and a proximal and a distal region, theproximal region having at least two lumens and the distal region havinga common lumen connected to and in communication with both lumens of theproximal region; an inflatable balloon disposed about at least a portionof the common lumen; a drive shaft having proximal and distal regions,the drive shaft disposed within a lumen of the proximal region of thecatheter body; and a work element coupled to the distal region of thedrive shaft, the work element positionable within the common lumen ofthe distal region of the catheter body.
 14. The catheter system of claim13, wherein the work element comprises an imaging device.
 15. Thecatheter system of claim 14, wherein the imaging device comprises anultrasonic transducer.
 16. The catheter system of claim 13, wherein thework element is positionable within the balloon.
 17. The catheter systemof claim 13, wherein the work element is extendible to a position pastthe balloon and into a blood vessel.
 18. The catheter system of claim15, wherein the work element is positionable within the balloon.
 19. Thecatheter system of claim 15, wherein the work element is extendible to aposition past the balloon and into a blood vessel.
 20. The cathetersystem of claim 19, wherein the work element comprises an imagingdevice.
 21. The catheter system of claim 20, wherein the imaging devicecomprises an ultrasonic transducer.
 22. The catheter system of claim 19,wherein the work element comprises an interventional device.
 23. Thecatheter system of claim 14, further comprising: an axially expandablemember connected to the proximal end of the catheter body; and aproximal housing connected to the proximal end of the drive shaft andthe axially expandable member, whereby the work element may be advancedfrom a position within a lumen of the proximal region into a positionwithin the common lumen of the distal region by moving the proximalhousing with respect to the catheter body.
 24. The catheter system ofclaim 20, further comprising: an axially expandable member connected tothe proximal end of the catheter body; and a proximal housing connectedto the proximal end of the drive shaft and the axially expandablemember, whereby the work element may be advanced from a position withina lumen of the proximal region into a position within the common lumenof the distal region by moving the proximal housing with respect to thecatheter body.
 25. The catheter system of claim 20, further comprising:an axially expandable member connected to the proximal end of thecatheter body; and a proximal housing connected to the proximal end ofthe drive shaft and the axially expandable member, whereby the workelement may be advanced from a position within a lumen of the proximalregion into a position past the balloon by moving the proximal housingwith respect to the catheter body.
 26. The catheter system of claim 20,further comprising: an axially expandable member connected to theproximal end of the catheter body; and a proximal housing connected tothe proximal end of the drive shaft and the axially expandable member,whereby the work element may be advanced from a position within a lumenof the proximal region into a position past the balloon and into a bloodvessel by moving the proximal housing with respect to the catheter body.27. The catheter system of claim 13, further comprising a ballooninflation means which includes a balloon inflation lumen disposedparallel to the two lumens of the proximal region.
 28. The cathetersystem of claim 13, wherein the balloon inflation lumen lies within thecatheter body at its proximal end and is disposed coaxially about thecommon lumen of the distal region of the catheter body.
 29. A method forimaging and treating a region of a patient's blood vessel using acatheter system comprising a guidewire; an imaging device fixed to adistal portion of a drive shaft; a catheter body having a proximalregion including at least two lumens, and a distal region including acommon lumen connected to and in communication with both lumens of theproximal region; and an inflatable balloon disposed about at least aportion of the distal region; the method comprising the steps of:advancing the guidewire in the blood vessel until a distal end portionof the guidewire lies within a region of interest, and a proximal endportion of the guidewire extends from the patient; moving the proximalend portion of the guidewire into the common lumen of the distal regionof the catheter body; advancing the catheter body into the blood vesseluntil the balloon and the common lumen lie within the region ofinterest; retracting the distal end portion of the guidewire out of thecommon lumen into a lumen of the proximal region of the catheter body;advancing the imaging device and drive shaft through a lumen of theproximal region of the catheter body into the common lumen; inflatingthe balloon to dilate the blood vessel; and imaging the area of interestwith the imaging device during the step of inflating the balloon. 30.The method of claim 29, wherein successive steps of imaging and ballooninflation are repeated as desired to reduce a stenosis at the region ofinterest to a desired extent.
 31. The method of claim 29, wherein theballoon is an angioplasty balloon.
 32. The method of claim 29, whereinthe step of advancing the imaging device includes advancing the imagingdevice into the balloon.
 33. The method of claim 29, wherein the step ofadvancing the imaging device includes advancing the imaging device pastthe balloon and into the blood vessel.
 34. A method for treating aregion of a patient's blood vessel using a catheter system comprising aguidewire; an interventional work element fixed to a distal region of adrive shaft; a catheter body having a proximal region including at leasttwo lumens, and a distal region including a common lumen connected toand in communication with both lumens of the proximal region; and anangioplasty balloon disposed about at least a portion of the distalregion; the method comprising the steps of: advancing the guidewire intothe blood vessel until a distal end portion of the guidewire lies withina region of interest and a proximal end portion of the guidewire extendsfrom the patient; moving the proximal end portion of the guidewire intothe common lumen of the distal region of the catheter body; advancingthe catheter body into the blood vessel until the angioplasty balloonand the common lumen lie in the region of interest; inflating theangioplasty balloon to dilate the blood vessel and reduce a stenosis atthe region of interest; retracting the distal end portion of theguidewire out of the common lumen into a lumen of the proximal region ofthe catheter body; advancing the interventional work element through alumen of the catheter body and through the common lumen into the bloodvessel; and treating the region of interest with the interventionaldevice.
 35. The method of claim 34, wherein the step of advancing theinterventional work element includes advancing the interventional workelement into the angioplasty balloon.
 36. The method of claim 34,wherein the step of advancing the interventional work element includesadvancing the interventional work element past the angioplasty balloonand into the blood vessel.